In a large system, such as a telecommunication system, it is common to enclose components, such as Printed Circuit Boards (PCBs), blades, or nodes, constituting the system inside a chassis 5, such as illustrated in FIG. 1. The chassis 5 allows designing scalable systems i.e. systems into which additional components can be added.
In order to allow the different components to communicate between them, each component is connected to a backplane 10, also illustrated in FIG. 1. A backplane is typically a PCB having slots into which other components such as PCBs, blades or cards, are plugged, and is typically just a connector without active surface mounted devices on it. The function of the backplane 10 is to carry the communication signals between the components. Typically a backplane is passive i.e. it does not require any external electrical power and it is built in such a way that copper traces can be used to exchange information between the components.
In most telecommunication systems, the backplane is designed to support a network topology such as a star, a dual-star 50 as illustrated in FIG. 2, a dual-dual-star or a fully-connected 75 network topology, as illustrated in FIG. 3. Depending on the network topology used when designing the backplane, more or less copper traces might be required, as shown in the FIGS. 2 and 3, where each circle represents a component and the lines in between the circles represent the interconnections between the components.
When the number of copper traces is important, such as in the case of a fully-connected network topology, the energy consumption also becomes important, as copper require a lot of energy in function of the distance to cover. In addition, copper traces are sensitive to interferences and offer a limited bandwidth capacity, which means that several parallel traces might be required to fulfill a given bandwidth requirement. Furthermore, since copper-based backplanes are passive, they provide a network topology adapted for use with a fixed or slightly variable number of components connected to it.